1. Field of the Invention
The present invention generally relates to a coupling for attachments to earth-moving or excavating machines, such as an excavator or backhoe. More particularly, the present invention relates to a low pressure, hydraulically operated, quick-coupling used to connect and disconnect a bucket or other operating tool to the boom or dipperstick of an excavator or backhoe and which is completely operable from within the cab or operator's chair of the machine.
2. Description of the Prior Art
Traditionally, the bucket of an excavator, backhoe or similar earth moving machine is attached to the boom or dipperstick arm through the use of pins inserted through brackets on the bucket and a hole through the end of the boom. Typically, the changing from one implement to another is a two person job. The operator would move the boom or dipperstick so that the end of the boom was positioned next to the bucket such that the pivot pins could be inserted by a second person through the holes in the brackets on the top of the bucket and in the end of the boom. A person on the ground would hand signal the operator up, down, back or forward in order to align the holes of the bucket and the boom. The pins are then inserted and secured. An entire operation, releasing a tool and attaching a new tool, took a great deal of time and effort since the tools being changed are typically very heavy and very cumbersome. Thus, it became apparent that a quick-coupling was required which would shorten the time needed to accomplish the above described operation and make it possible for only the operator without assistance by another person to accomplish the changing from within the cab of the backhoe or excavator.
The prior art discloses many types of quick-couplings for attaching a bucket or other tool to the boom or loader scoop arm of a backhoe, loader or other similar earth moving machine. For example, the following patents disclose and teach couplings which are improvements over the traditional method but still require some type of physical intervention to effect the changing of the tool: U.S. Pat. Nos. 4,030,624, to Matthews; 4,187,050, to Barbee; 4,295,287, to Natzke et al.; 4,373,852, to Maurer; 4,632,595, to Schaeff; and 4,643,631, to Maurer et al.
In addition to the above, U.S. Pat. No. 4,836,741, to St. Louis et al. discloses a quick coupling for detachably connecting a bucket to a boom, an excavator or a backhoe. St. Louis et al. disclose a main body adapted to be connected to a boom or dipperstick of an excavator or backhoe. A bucket or other implement has a pair of industry-standard, spaced apart, contoured, support brackets welded thereto for connection to the boom or dipperstick. A first pair of aligned and opposite apertures in each of the support brackets contain a first upper bucket pin. A second pair of aligned and opposite apertures in each of the support brackets are spaced a predetermined distance from the first pair containing the first upper bucket pin. St. Louis et al. disclose that the main body has a transverse hook formed therein for receiving the first upper bucket pin and a bore spaced a predetermined distance from the transverse hook such that in the connected position the bore aligns with the second pair of aligned and opposite apertures in the support brackets of the bucket. St. Louis et al. teach that an eccentric bushing is displaced within the bore and then rotated to align the bore with the second pair of apertures on the bucket so that a pin can then be manually inserted and secured in place.
U.S. Pat. No. 4,480,955, to Andrews et al. discloses a quick release and attachment coupling for use with an earth moving or excavating machine. Andrews et al. disclose that a V-shaped slot is provided on one side of the head of the boom in which a transverse bar or beam of the tool is located, then a movable block in the head of the boom is moved by a hydraulic ram into engagement with a hook or jaw on the tool to lock the head of the boom to the operating tool. A drawback of the Andrews et al. device is that it requires the operating tool to be specially equipped in order to be used with the Andrews et al. quick release and attachment coupling. As a result the Andrews et al. coupling cannot be used with what is considered to be the industry standard coupling for an attachment to an excavator. Similar to Andrews is U.S. Pat. No. 4,297,074, to Ballinger, which also discloses a coupling for an implement, and like the Andrews device, is not compatible with an industry standard implement having a pair of spaced apart pivot pins for attachment to the excavator or backhoe.
The Hendrix-J. B. Quick Coupler disclosed in the publication entitled THE MOST VERSATILE HYDRAULIC COUPLER IN THE WORLD, discloses a quick coupler for use with an excavator which allows an operator to quickly change from one implement to another. The quick coupler disclosed is essentially a pair of hooks disposed so as to cooperate with a pair of pins located on the implement to be attached. The first hook is fixed and the second hook of the quick coupling is hydraulically operable between an open and a closed position. Springs are provided to bias the second hook in the closed position and a hydraulic piston is operable to open the second hook in order to release or grasp the pin of the implement. However, the Hendrix Coupler is expensive because it requires a specially manufactured housing to contain the second hydraulically operable hook and springs. Additionally, the Hendrix coupler is not completely safe because if the weight of the implement and load exceed the bias force of the springs, the implement could break free from the quick coupler.
As the above-mentioned patents disclose, it is well known to provide a device which will allow for quick changing of the bucket or other working tool connected to an earth-working machine, such as an excavator or backhoe. It is also well known that it is advantageous to provide a device which will accomplish this task remotely from the operator's position because changing from one bucket or tool to another is time consuming and labor intensive and therefore costly. Thus, what is needed is to provide an apparatus which makes it possible for the operator, without any help or any need to leave the controls of the machine, to quickly and easily exchange the bucket or other working tool connected to the boom of the machine for another tool. However, none of the prior art references disclose a quick disconnect coupling device which is cost effective, requires a minimal amount of time to install and is completely failsafe.